We present a hybrid time-dependent d. functional/mol. mechanics (TDDFT/MM) simulation study on the optical properties of aminocoumarins in gas phase and soln. As solvation is described through a mol. approach, the effects due to the inhomogeneities of the elec. field of the solvent mols. are fully included. We focus on the ground state and first excited singlet state properties of C151, C35 and C153, three aminocoumarins for which a homogeneous set of exptl. data is available. Our approach is able to give quant. information on the red shifts in water and acetonitrile, two solvents which show different H-bonding properties. In addn., it is able to quantify the effects of chem. substituents, such as the spectral red shift due to the increased alkylation at the amino position. [on SciFinder (R)]